The present invention relates to an identification signal checking apparatus and an identification signal checking method which are suitable for use in a keyless entry system.
A keyless entry system has been proposed. In this keyless entry system, infrared rays or radio waves are used to transmit an identification signal from a key apparatus side to a lock apparatus side for the locking or the unlocking.
Such keyless entry system employs a one-way communication in which the key apparatus side constantly transmits the same identification signal. Therefore, when this communication is intercepted, the identification signal may disadvantageously be stolen easily.
Particularly when the identification signal is transmitted by using the infrared rays, it is possible to copy the identification signal easily by a so-called learning remote controller, which has already been developed into a social problem.
Moreover, since in the above keyless entry system it is possible to detect a specific identification signal by using each of various identification signals to detect whether or not each of the identification signals is agreed with the specific identification signal, there is the critical disadvantage in security.